Application programs often produce output for printing on paper. This output often includes text in a variety of fonts, images, graphics, bar codes, and the like. The application output may be expressed as a data stream comprising a well defined set of commands. These commands allow a computer to tell a printer what and where to print. The output data stream is often held in a file prior to printing. Many formats for data streams have been developed. Two of the most common data stream formats are PostScript and Advanced Function Presentation (AFP).
PostScript was developed by Adobe, Inc. PostScript was the first data stream having its own stack and programming language capabilities. PostScript includes scalable fonts, smooth greyscaling, and multiple orientations on the physical page. Enhancements to PostScript permit a set of operations to be grouped in a form, multiple methods for specifying color, and composite fonts for unlimited character sets. PostScript is a registered trademark of Adobe, Inc.
AFP presentation data streams include text and in-line resources, such as form definitions and page definitions, to construct a data stream that then points to overlays, page segments, fonts, and the like. AFP is all points addressable, meaning that any location on the printed page can be addressed by a command in the data stream.
A file holding a data stream in one format may have to be converted to another format. This may occur, for example, when transferring output data from an installation using the first data format to an installation using the second data format.
What is needed is an efficient method to convert a file written in the AFP format to a file written in the PostScript format.